Mozilla Labs Unveils Jetpack API

By Nathan Eddy |
Posted 2009-05-22

Mozilla Labs' virtual lab development team has announced the debut of
Jetpack, a newly formed browser enhancer using open Web technologies.

The API allows users to write Firefox
add-ons. The launch site notes the project includes pre-release software that is
still being actively designed and developed, and is being made available for
developers and testers only.

The site also contains a list of guiding principles for what Mozilla Labs calls
an "experiment," including a foundation solely Web-based (HTML, JavaScript and CSS
will be the only tools required), and the ability to debug the browser without
restarting using common Web development tools like Firebug.

The lab puts a strong focus on the "develop once, run anywhere" guideline,
noting add-ons should be able to run in Firefox Mobile, Thunderbird and
"anywhere else." Mozilla states developers shouldn't have to worry about some
internal change in Firefox breaking extensions. "Add-ons will work through a version'ed
facade-pattern so that you won't be in a constant struggle to keep your
extension working with the latest FF edition," the lab points out.

Security is also one of the four main headings for guiding principles; Jetpack
is designed to provide access to only the privileges needed, with security
issues always presented in social terms, not technical terms. "Short and easy to
review code ensures that potential security issues are shallow, and review
times short," reads a blog post by Aza Raskin, Atul Varma
and Nick Nguyen from the Jetpack development team.

Mozilla also wants to keep Jetpack extensible with architecture that will allow
for the easy inclusion of reviewed and versioned third-party tool kits like
jQuery or Dojo and API libraries like
Twitter, Delicious or Google Maps. Also included on the site are two
demonstrations, one for an e-mail notifier and the UnAd content filter demo,
which demonstrates in about 80 lines of code how to build a Jetpack feature
that can remove unwanted scripts, images and iframes with a "pretty UI" for
turning the feature on and off.

Several other demonstrations can also be viewed, though the majority are
notifiers of a kind. Mozilla Labs is also taking great care to alert
programmers to the potential dangers of third-party Jetpack features. "The
features referenced here have not been reviewed by Mozilla," a warning on the
page states. "They may contain malicious code, so use them only at your own
risk."

The three Labs members also encourage programmers to join the project. "Mozilla
Labs is a virtual lab where people come together online to create, experiment
and play with Web innovations for the public benefit. The Jetpack experiment is
still in its infancy and just getting started," they wrote. "As with all Labs
experiments, Jetpack is an open source project and everyone is welcome to
participate in its design, development and testing."